Assessment of blast furnace behaviour through softening-melting test

Blast furnace operation is a complex phenomenon; maximising productivity requires a balance of burden characteristics. Meeting the targets of optimum sinter strength and minimum slag volume is a matter of concern for high alumina (2.0-2.1%) iron ore fines. To achieve reduced slag volume MgO in the sinter may be reduced and sinter strength maintained by addition of coke breeze. However, the associated increase in fuel rate during sintering raises the FeO content. The effects of increasing FeO and lowering MgO on the softening melting behaviour of burden materials have been assessed in laboratory experiments and the results compared with data from blast furnace operations at Tata Steel. It was found that with sinter containing > 12% FeO, erratic furnace behaviour was encountered and energy adjustment was required with the reduction in MgO (1.77-1.48%) to ensure smooth operation.